Paleolithic European mtDNA

Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe (free full text):

How modern humans dispersed into Eurasia and Australasia, including the number of separate expansions and their timings, is highly debated [ 1, 2 ]. Two categories of models are proposed for the dispersal of non-Africans: (1) single dispersal, i.e., a single major diffusion of modern humans across Eurasia and Australasia [ 3–5 ]; and (2) multiple dispersal, i.e., additional earlier population expansions that may have contributed to the genetic diversity of some present-day humans outside of Africa [ 6–9 ]. Many variants of these models focus largely on Asia and Australasia, neglecting human dispersal into Europe, thus explaining only a subset of the entire colonization process outside of Africa [ 3–5, 8, 9 ]. The genetic diversity of the first modern humans who spread into Europe during the Late Pleistocene and the impact of subsequent climatic events on their demography are largely unknown. Here we analyze 55 complete human mitochondrial genomes (mtDNAs) of hunter-gatherers spanning ∼35,000 years of European prehistory. We unexpectedly find mtDNA lineage M in individuals prior to the Last Glacial Maximum (LGM). This lineage is absent in contemporary Europeans, although it is found at high frequency in modern Asians, Australasians, and Native Americans. Dating the most recent common ancestor of each of the modern non-African mtDNA clades reveals their single, late, and rapid dispersal less than 55,000 years ago. Demographic modeling not only indicates an LGM genetic bottleneck, but also provides surprising evidence of a major population turnover in Europe around 14,500 years ago during the Late Glacial, a period of climatic instability at the end of the Pleistocene.

4 comments:

4 February 2016Mystery invaders conquered Europe at the end of last ice age

Europe went through a major population upheaval about 14,500 years ago, at the end of the last ice age, according to DNA from the bones of hunter-gatherers.

Ancient DNA studies published in the last five years have transformed what we know about the early peopling of Europe. The picture they paint is one in which successive waves of immigration wash over the continent, bringing in new people, new genes and new technologies.

These studies helped confirm that Europe’s early hunter-gatherers – who arrived about 40,000 years ago – were largely replaced by farmers arriving from the Middle East about 8000 years ago. These farmers then saw an influx of pastoralists from the Eurasian steppe about 4500 years ago, meaning modern Europe was shaped by three major population turnover events.Waves of immigration

The latest study suggests things were even more complicated. About 14,500 years ago, when Europe was emerging from the last ice age, the hunter-gatherers who had endured the chilly conditions were largely replaced by a different population of hunter-gatherers.

Exactly where this new population came from is still unclear, but it seems likely that they came from warmer areas further south. “The main hypothesis would be glacial refugia in south-eastern Europe,” says Johannes Krause at the Max Planck Institute for the Science of Human History in Jena, Germany, who led the analysis.

As conditions improved, it was these southern hunter-gatherers who took advantage and migrated into central and northern Europe, he says – meaning there was a genetic discontinuity with the hunter-gatherer populations that had lived there earlier.